1. Field of the Invention
The present invention relates to a honeycomb structural body and an exhaust gas conversion apparatus.
2. Discussion of the Background
Exhaust gas of automobiles contain substances such as hydrocarbon compounds, carbon monoxide, and nitrogen oxide. A honeycomb structural body formed of cordierite is used for converting the exhaust gas. The honeycomb structural body includes plural through-holes partitioned by cell walls in which the surface of the cell walls is formed of a catalyst carrying layer formed of alumina. Catalysts such as platinum, rhodium, and palladium are carried on the catalyst carrying layer.
However, in a case where the temperature of the exhaust gas decreases, it becomes difficult for the catalyst carried on the catalyst carrying layer to sufficiently function (activate). This results in a problem of the exhaust gas converting function of the honeycomb structural body being easily degraded.
In JP-U-49-124412, there is disclosed a catalytic exhaust gas converting apparatus related to an internal combustion engine in which a heating element such as silicon carbide used as the base material of a honeycomb unit, an integral structure catalyst body formed of a single honeycomb unit is installed in a container for catalyst support connected to an exhaust gas passage by interposing an insulating member, and an outer peripheral portion of the catalyst body is connected to a terminal. Only in a condition where the catalyst body is in an atmosphere of a predetermined temperature, the catalyst body is heated by heating the base material of the honeycomb unit with a charge from a power source via the terminal on the catalyst body.
JP-P-7-80226 discloses an exhaust gas filter for converting exhaust gas of an internal combustion engine in which the exhaust gas filter is formed of an assembly of plural porous ceramic filters and a pair of self-heating electrodes provided on both ends thereof.
JP-U-49-124412 and JP-P-7-80226 are incorporated herein.